In a mobile communications network, an idle service is one of basic mobile services. If the idle service is implemented in the mobile communications network, if a mobile terminal is idle, a radio link is faulty, or a base station is faulty, an air interface connection between the mobile terminal and the base station is released, and the mobile terminal enters an idle state. When a core network needs to send a packet to the mobile terminal, the mobile terminal then sets up a connection to the core network, and enters a non-idle state to receive the packet from the core network.
An implementation process of the idle service includes an S1-Release procedure, a Service Request procedure, and a Paging procedure. If the mobile terminal is idle, the radio link is faulty, or the base station is faulty, the mobile terminal releases the air interface connection to the base station by using the S1-Release procedure, so that the mobile terminal enters the idle state; and when the mobile terminal enters the idle state, a network element of the core network still retains a tunnel that the mobile terminal sets up when accessing the network. When the network element of the core network receives a packet that needs to be sent to the mobile terminal, the network element initiates the Paging procedure to page the mobile terminal, that is, the network element triggers, by using the tunnel corresponding to the mobile terminal, the base station to page the mobile terminal. After the mobile terminal is paged, the mobile terminal sets up a connection to the network element by performing the Service Request procedure, and then the network element forwards the packet to the mobile terminal by using the connection.
In the mobile communications network, the network element can initiate the Paging procedure to page the mobile terminal; therefore, the network element has a control function. The network element can further receive the packet that needs to be sent to the mobile terminal, and forward the packet to the mobile terminal; therefore, the network element has a forwarding function. Because the network element has both the control function and the forwarding function, the network element has relatively high costs. During network coverage extension and area expansion, more network elements are added to the mobile communications network; however, the network elements have relatively high costs, which results in relatively high costs of network coverage extension and area expansion.
To reduce costs of network upgrade extension and expansion, at present, an SDN (software defined networking) network architecture is integrated into the mobile communications network. In the mobile communications network that integrates the SDN network architecture, the control function is implemented by a network controller, and the forwarding function is implemented by a forwarding entity, thereby implementing separation of the control function and the forwarding function. Because the forwarding entity has no control function but universality, costs of the forwarding entity are less than the costs of the foregoing network element. During network upgrading and expansion, only more forwarding entities need to be added, thereby reducing costs of network coverage extension.
In the mobile communications network that integrates the SDN network architecture, when the air interface connection between the mobile terminal and the base station is released and a network side has a packet to send to the mobile terminal, there is no mechanism to wake up the mobile terminal, so as to send the packet to the mobile terminal.